PROJECT SUMMARY Despite decreasing adult HIV mortality, HIV mortality rates among adolescents remain stable and high. It is necessary to understand influencing factors to ensure transition of care from pediatric to adult HIV care and provide sufficient support to adolescents during this vulnerable time. Tuberculosis (TB) causes significant morbidity and mortality among people living with HIV (PLHIV) and adolescents are at a particularly high risk for TB. The cascade of care in TB, from intensified case finding to TB cure/preventative treatment completion, has not been well defined in sub-Saharan Africa and may differ between adolescents and adults. The focus of the first aim will be to describe and assess the cascade of TB preventive care among HIV-infected adolescents in Kenya utilizing medical record abstraction and electronic medical records. In the second aim, we will assess facility level determinants of isoniazid preventive therapy (IPT) initiation, continuation, and completion using facility surveys from 102 facilities in Kenya. In our third aim, we will identify individual level determinants of adolescent IPT initiation, continuation, and completion among 10,000 adolescent HIV clients from selected clinics. This study will be conducted in partnership with the University of Nairobi and Kenyatta National Hospital, organizations that have conducted research with the University of Washington for more than 25 years. Individual level data will be obtained from manual medical record abstraction and from electronic medical records. Facility surveys will be distributed to randomly selected facilities among the 102 clinics with electronic medical record systems. This diversity supplement will build on the innovative implementation science approach of the parent grant ?Transitioning from Pediatric to Adult HIV care in Kenya? (R01HD089850-01). It will expand upon current co-factors of interest for successful transition, by focusing on intensified case finding and IPT use and how facility and individual level factors modulate initiation and completion of TB preventive therapy. This data will help identify barriers and/or facilitators to IPT use and be essential to improve quality of life for HIV-infected adolescents.